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A team of 20 scientists, led by astrobiologist Dirk Schulze-Makuch of Washington State University, wants to send a fleet of sensor packages to Mars. The mission is called Biological Oxidant and Life Detection or BOLD.

Dr. Schulze-Makuch said, “We really want to address the big questions on Mars and not fiddle around.” With money for space science drying up, Schulze-Makuch says NASA needs to get exciting results that interest not only scientists but the general public as well.

The BOLD mission would drop six 130-pound probes at chosen locations. The probes would parachute to the surface, then insert a soil sampler nearly a foot into the ground .

The flotilla of probes harkens back to the network-science concept that was a theme of NASA’s New Millennium program in the 1990’s. Unfortunately, that approach was abandoned when the New Millennium program ended.

Each probe would conduct six experiments. A microscope would examine the sample for shapes similar to terrestrial microorganisms and microfossils. Another instrument would look for long-chain molecules similar to nucleic acids. A soil analyzer would measure inorganic ions, pH, and optical characteristics to determine the concentration of hydrogen peroxide.

Other instruments would repeat experiments performed by Viking. Schulze-Makuch has argued that old data from the Viking landers might actually contain evidence of life.

According to Schulze-Makuch, recent findings about extremophile organisms on Earth warrant a new look at Viking data. He has hypothesized that Mars might be home to microorganisms that contain a solution of hydrogen peroxide and water. Such a solution would have a freezing point as low as -56.5 C, depending on the peroxide concentration. Below that temperature, it would freeze without forming crystals that destroy cells, as water does. Hydrogen peroxide is also hygroscopic, so it would attract water vapor from the thin Martian atmosphere.

Schulze-Makuch believes that stabilizing agents could protect cells from hydrogen peroxide’s powerful disinfecting properties. Peroxide can also perform useful biological functions. On Earth, Acetobacter peroxidans is a the bacterial species that uses hydrogen peroxide in its metabolism. The bombardier beetle (genus Brachinus) produces a solution of 25% hydrogen peroxide which it uses as a defensive spray.

Peroxide-based organisms could explain many of the Viking results. Because hydrogen peroxide is a strong oxidant, its release from dying cells would destroy nearby organic material. (Viking’s gas chromatograph-mass spectrometer detected no organic compounds on Mars.) Patchy distribution of peroxide-based organisms could explain the results of the Pyrolytic Release experiment, which showed significant production of organic substances in three out of seven samples. The lowest organic production was found in a sample treated with water, however, which could be fatal to peroxide-based organisms. The Labeled Release experiment showed rapid production of carbon dioxide which then leveled off. The initial release could have been due to metabolism by peroxide-based organisms organisms which then began dying from the experimental conditions.

“If the hypothesis is true, it would mean that we killed the Martian microbes during our first extraterrestrial contact by drowning due to ignorance,” Schulze-Makuch said.